A new paper-plastic composite material that is easy to recycle

Abstract

The present invention provides a novel paper-plastic composite packaging material, comprising a first barrier layer plastic resin film layer, a second water-based coating layer and a third base paper layer; wherein the water-based coating used contains 30-55% of acrylic ester polymer, 0.1-0.5% of defoaming agent, 1-5% of water-based wax emulsion, and the rest is deionized water. After the service life of the novel paper-plastic composite packaging material prepared by the present invention ends, paper and plastic can be easily separated and put into their respective recycling systems respectively, so as to complete the classified recycling of paper and plastic, and then reuse them, thus overcoming the problem that the existing paper-plastic composite materials cannot be recycled in a classified manner due to the difficulty in separating the two during recycling, and can only be mixed into the same recycling system as a whole, and then separated by physical and / or chemical methods, and then recycled separately, which increases the cost and energy consumption of recycling.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging materials, and in particular relates to a novel paper-plastic composite material which is easy to recycle and reuse. Background Art

[0002] Paper-plastic composite material is a material made of paper and plastic through composite processing. Paper-plastic composite material combines the advantages of paper and plastic. The paper part is printed and other processes to make the surface of the product present various patterns and colors, with good appearance, and the plastic part provides good mechanical strength and barrier properties for the product.

[0003] The material can be recycled and reused to save natural resources and reduce pollution to the environment, making it an environmentally friendly material. In paper-plastic composite materials, the paper part can be recycled and re-pulped and re-made into paper, and the plastic part can be recycled and re-granulated to achieve the reuse of resources.

[0004] However, although both the paper and plastic parts of paper-plastic composite materials can be recycled, they are often difficult to separate and cannot be recycled separately. They can only be mixed into the same recycling system as a whole, and then the paper and plastic are separated by physical and / or chemical methods, and then recycled separately, which increases the cost and energy consumption of recycling. Summary of the invention

[0005] The purpose of the present invention is to provide a novel paper-plastic composite packaging material, which can easily separate paper and plastic after the end of its service life and put them into their respective recycling systems to complete the classified recycling of paper and plastic, and then reuse them.

[0006] The present invention first provides a water-based coating for preparing a paper-plastic composite packaging material, wherein the water-based coating comprises 30-55% of an acrylate polymer, 0.1-0.5% of a defoamer, 1-5% of an aqueous wax emulsion, and the remainder is deionized water;

[0007] As a preferred embodiment, the acrylate polymer is preferably an acrylic polymer which is solid below 100°C and viscous above 100°C after drying;

[0008] The aqueous wax emulsion has a particle size of 10 to 500 nanometers;

[0009] Furthermore, the acrylic polymer preferably has a mass fraction of 35%, the defoamer preferably has a mass fraction of 0.3%; the aqueous wax emulsion (particle size 10-500 nanometers) preferably has a mass fraction of 3%; and the deionized water preferably has a mass fraction of 61.7%.

[0010] The water-based coating provided by the present invention can be used to prepare paper-plastic composite packaging materials;

[0011] As a specific description of an embodiment, the paper-plastic composite packaging material comprises a first barrier layer plastic resin film layer, a second water-based coating layer and a third base paper layer;

[0012] As a preferred embodiment, the barrier layer plastic resin film layer is preferably polyethylene terephthalate PET, polypropylene PP or polyethylene PE;

[0013] Furthermore, the thickness of the PET resin film is preferably 6 to 20 μm;

[0014] As a preferred embodiment, the base paper layer is selected from 20-350 g / m 2 Paper for packaging materials;

[0015] A specific preparation method of the novel paper-plastic composite material provided by the present invention is as follows:

[0016] 1) adding an acrylic acid ester polymer, a defoaming agent, an aqueous wax emulsion and deionized water into a dispersing stirring kettle, stirring and dispersing at 5-35° C. and a rotation speed of 200-1500 r / min for not less than 1 hour to obtain a water-based coating;

[0017] 2) Pre-apply the water-based coating to the corona surface of the barrier plastic resin film layer, dry it in a drying oven, then melt the paper-plastic separation water-based coating under heating, and then laminate it with the base paper layer, and reel it up after cooling.

[0018] The novel paper-plastic composite packaging material prepared by the present invention can easily separate paper and plastic after the service life ends, and put them into their respective recycling systems respectively, so as to complete the classified recycling of paper and plastic, and then reuse them, thereby overcoming the problem that the existing paper-plastic composite materials cannot be recycled separately due to the difficulty in separating the two during recycling, and can only be mixed into the same recycling system as a whole, and then the paper and plastic are separated by physical and / or chemical methods, and then recycled separately, which increases the cost and energy consumption of recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : Schematic diagram of the layered structure of the novel paper-plastic composite material of the present invention;

[0020] Figure 2 : The paper-plastic separation effect diagram of the novel paper-plastic composite material of the present invention;

[0021] Figure 3 : An enlarged view of the paper-plastic separation effect of the novel paper-plastic composite material of the present invention. DETAILED DESCRIPTION

[0022] When existing paper-plastic composite materials are recycled, they are often difficult to separate and cannot be recycled separately. They can only be mixed into the same recycling system as a whole, and then separated by physical and / or chemical methods, and then recycled separately, which increases the cost and energy consumption of recycling.

[0023] In order to overcome the above shortcomings, the present invention uses base paper and plastic resin film as substrates, uses a water-based acrylic heat-seal coating as raw material, and adopts different layered structures, so that after the service life of the paper and the plastic is over, the paper and the plastic can be easily separated and respectively put into their respective recycling systems to complete the classified recycling of the paper and the plastic, and then reuse them, thereby solving the problem that the existing paper-plastic composite materials cannot be recycled separately during recycling due to the difficulty in separating the two, and can only be mixed into the same recycling system as a whole, and then the paper and the plastic are separated by physical and / or chemical methods, and then recycled separately, which increases the cost and energy consumption of recycling, thereby making up for the shortcomings of the prior art.

[0024] The present invention first optimizes and selects the paper-plastic separation water-based coating, and screens from hot melt adhesive system, polyurethane system and acrylic system. The hot melt adhesive system is a plastic adhesive, the main component of which is EVA resin; the polyurethane system refers to an adhesive containing a carbamate group (-NHCOO-) or an isocyanate group (-NCO) in the molecular chain, mainly a polyurethane dispersion; and the acrylic system adhesive is a copolymer with acrylic esters as the main monomer.

[0025] Furthermore, the hot melt adhesive system used in Comparative Example 1 is sold by Henkel of Germany under the product number TECHNOMELT PS203L;

[0026] Further, the polyurethane system adhesive used in Comparative Example 2 is sold by Henkel of Germany under the product number AQUENCE PL 107A-T;

[0027] Furthermore, the acrylic adhesive used in the specific embodiment is sold by Henkel of Germany under the product number LOCTITE LIOFOL HS2809-22RE;

[0028] The acrylic adhesive used in the present invention is preferably an acrylic ester polymer which is solid below 100°C and viscous above 100°C after drying;

[0029] In order to avoid the influence of the parameter fluctuation of the third base paper layer itself, such as quantitative and water absorption, on the paper coating, the paper-plastic separation water-based coating to be screened was studied. When screening the coating, the paper-plastic separation coating was applied to the first barrier layer plastic resin film layer, and then compounded with the base paper layer. The coating amount was 2g / m 2 (dry weight), cooled and rolled after drying, the drying temperature is 105±5℃, the machine speed is 80m / min, and placed at room temperature 25±2℃ and relative humidity 60% for 24 hours. Three types of paper are cut and tested respectively. The peel strength is ≥2N / 15mm, whether the surface of the third base paper layer is damaged, and whether the plastic resin film layer of the first barrier layer is damaged are used as the evaluation basis. The result data are shown in Table 1.

[0030] Table 1: Experimental data of water-based coatings of different systems

[0031]

[0032] As can be seen from Table 1, the peel strength of the paper-plastic composite material prepared using hot melt adhesive system adhesive and polyurethane system adhesive is too high, resulting in damage to the base paper layer, and further, the first barrier layer plastic resin film layer and the third base paper layer are difficult to separate. The peel strength of the paper-plastic composite material prepared using acrylic system adhesive is moderate, and when the paper-plastic is peeled, both the base paper layer and the barrier layer plastic resin film layer are damaged.

[0033] Combining the above data, it is concluded that acrylic system adhesive is used as the second layer of water-based coating for paper-plastic separation.

[0034] In order to obtain a paper-plastic separation water-based coating with stable peeling strength and prevent the occurrence of regional or point-like high peeling strength, the acrylic system adhesive is fine-tuned with other components to obtain a new paper-plastic separation water-based coating, which contains 30-55% of acrylate polymer, 0.1-0.5% of defoamer, 1-5% of water-based wax emulsion, and the rest is deionized water;

[0035] As a preferred embodiment, the acrylate polymer is preferably an acrylic polymer which is solid below 100°C and viscous above 100°C after drying;

[0036] The aqueous wax emulsion has a particle size of 10 to 500 nanometers;

[0037] Furthermore, the acrylic polymer preferably has a mass fraction of 35%, the defoamer preferably has a mass fraction of 0.3%; the aqueous wax emulsion (particle size 10-500 nanometers) preferably has a mass fraction of 3%; and the deionized water preferably has a mass fraction of 61.7%.

[0038] The defoamer used in the embodiments of the present invention is an organic oil food-grade defoamer produced by Dow Chemical, with the brand name Airase 4500.

[0039] The aqueous wax emulsion used in the embodiments of the present invention is an aqueous wax emulsion produced by Keim-additec of Germany, with the brand name E-325.

[0040] The technical solution is further described below in conjunction with the accompanying drawings and embodiments.

[0041] Comparative Example 1

[0042] The present invention provides a paper-plastic composite material, comprising a first base paper layer, a second paper-plastic separation water-based coating layer, and a third barrier layer composed of a plastic resin film layer. The paper-plastic separation water-based coating layer is applied to the corona surface of the barrier plastic resin film layer, and is laminated to the base paper layer, dried, cooled, and then rolled up; wherein the paper-plastic separation water-based coating layer is a hot melt adhesive system adhesive.

[0043] The preparation method of the provided paper-plastic composite material is as follows: first, at least one side of the barrier layer plastic resin film layer 3 is corona treated, and the dyne value is ≥38, and the paper-plastic separation water-based coating 2 is heated and melted and then applied to the corona surface of the barrier layer plastic resin film layer 3, and then laminated with the base paper layer 1, and then rolled up after drying and cooling treatment, the drying temperature is 105±5℃, and the machine speed is 80 meters / minute.

[0044] Comparative Example 2

[0045] The paper-plastic separation water-based coating 2 used in this embodiment is a polyurethane system adhesive. The preparation method of the prepared paper-plastic composite material is as follows: first, at least one side of the barrier layer plastic resin film layer 3 is corona treated, and the dyne value is ≥38. The paper-plastic separation water-based coating 2 is applied to the corona surface of the barrier layer plastic resin film layer 3 by a coating process, and is laminated to the base paper layer 1. After drying and cooling treatment, it is rolled up. The drying temperature is 105±5°C and the machine speed is 80 m / min.

[0046] Example 3

[0047] like Figure 1 and Figure 2 As shown, the paper-plastic composite material provided by the present invention includes a first base paper layer 1, a second paper-plastic separation water-based coating 2, and a third barrier layer 3 composed of a plastic resin film layer. The paper-plastic separation water-based coating 2 is pre-coated on the corona surface of the barrier layer plastic resin film layer 3, dried in a drying oven, and then the water-based acrylic heat-sealing coating is melted under heating, and then bonded to the base paper layer, and rolled up after cooling. The paper-plastic separation water-based coating 2 includes 35% acrylate polymer (Henkel LOCTITE LIOFOL HS2809-22RE), 0.3% defoaming agent, 3% water-based wax emulsion, and 61.7% deionized water;

[0048] The above-mentioned paper-plastic separation water-based coating is used to prepare a new paper-plastic composite material:

[0049] The specific preparation method is as follows: firstly, corona treatment is performed on at least one side of the barrier layer plastic resin film layer 3, and the dyne value is ≥38; the paper-plastic separation water-based coating 2 is applied to the corona surface of the barrier layer plastic resin film layer 3 by a coating process; the paper-plastic separation water-based coating 2 is dried in a drying oven at a temperature of 85±5°C; then, the paper-plastic separation water-based coating 2 is heated in the next drying oven to melt the paper-plastic separation water-based coating 2 and bond it to the base paper layer 1 at a heating temperature of 125±5°C; and the paper-plastic separation water-based coating 2 is rolled up after cooling treatment at a machine speed of 80 m / min.

[0050] The structures of the paper-plastic composite materials prepared in the following Examples 4-8 are similar to those in Example 3, except that the steps of the preparation methods are different.

[0051] Example 4

[0052] In this embodiment, the paper-plastic separation water-based coating 2 includes 35% of acrylate polymer (Henkel LOCTITE LIOFOLHS2809-22RE), 0.3% of defoamer, 3% of water-based wax emulsion, and 61.7% of deionized water;

[0053] The preparation method is as follows: first, corona treatment is performed on at least one side of the barrier layer plastic resin film layer 3, and the dyne value is ≥38. The paper-plastic separation water-based coating 2 is applied to one side of the base paper layer 1 by a coating process, and then dried in a drying tunnel at a temperature of 85±5°C. Then, it is heated in the next drying tunnel to melt the paper-plastic separation water-based coating 2 and adhere to the corona surface of the barrier layer plastic resin film layer 3. The heating temperature is 125±5°C. After cooling treatment, it is rolled up at a machine speed of 80 m / min.

[0054] Example 5

[0055] The paper-plastic separation water-based coating 2 used in this embodiment includes 35% of acrylate polymer (Henkel LOCTITE LIOFOLHS2809-22RE), 0.3% of defoamer, 3% of water-based wax emulsion, and 61.7% of deionized water;

[0056] The specific preparation method is as follows: first, corona treatment is performed on at least one side of the barrier layer plastic resin film layer 3, and the dyne value is ≥38. The paper-plastic separation water-based coating 2 is applied to one side of the base paper layer 1 and the corona surface of the barrier layer plastic resin film layer 3 by a coating process, respectively, and dried in a drying tunnel at a temperature of 85±5°C, and then heated in the next drying tunnel to melt the paper-plastic separation water-based coating 2, and then the side of the base paper layer 1 pre-coated with the paper-plastic separation water-based coating 2 and the side of the barrier layer plastic resin film layer 3 pre-coated with the paper-plastic separation water-based coating 2 are laminated, the heating temperature is 125±5°C, and the paper-plastic separation water-based coating 2 is pre-coated on the side of the barrier layer plastic resin film layer 3, and the paper-plastic separation water-based coating 2 is pre-coated on the side of the base paper layer 1, and the paper-plastic separation water-based coating 2 is pre-coated on the side of the barrier layer plastic resin film layer 3, and the heating temperature is 125±5°C, and the paper-plastic separation water-based coating 2 is rolled up after cooling treatment, and the machine speed is 80 meters / minute.

[0057] Example 6

[0058] In this embodiment, the paper-plastic separation water-based coating 2 includes 35% of acrylate polymer (Henkel LOCTITE LIOFOLHS2809-22RE), 0.3% of defoamer, 3% of water-based wax emulsion, and 61.7% of deionized water;

[0059] The specific preparation method is as follows: first, corona treat at least one side of the barrier layer plastic resin film layer 3, and the dyne value is ≥38. The paper-plastic separation water-based coating 2 is applied to the corona surface of the barrier layer plastic resin film layer 3 by a coating process, and then laminated to the base paper layer 1. After drying and cooling treatment, it is rolled up. The drying temperature is 105±5℃ and the machine speed is 80 m / min.

[0060] Example 7

[0061] The paper-plastic separation aqueous coating 2 used in this embodiment includes 35% of acrylate polymer (Henkel LOCTITELIOFOL HS2809-22RE), 0.3% of defoamer, 3% of aqueous wax emulsion, and 61.7% of deionized water;

[0062] The above-mentioned paper-plastic separation water-based coating is used to prepare a new type of paper-plastic composite material, and its specific preparation method is as follows: first, at least one side of the barrier layer plastic resin film layer 3 is corona treated, and the dyne value is ≥38. The paper-plastic separation water-based coating 2 is applied to one side of the base paper layer 1 by a coating process, and is laminated with the corona surface of the barrier layer plastic resin film layer 3. After drying and cooling treatment, it is rolled up. The drying temperature is 105±5℃ and the machine speed is 80 meters / minute.

[0063] Example 8

[0064] The paper-plastic separation water-based coating 2 used in this embodiment includes 35% of acrylate polymer (Henkel LOCTITE LIOFOLHS2809-22RE), 0.3% of defoamer, 3% of water-based wax emulsion, and 61.7% of deionized water;

[0065] The above-mentioned paper-plastic separation water-based coating is used to prepare a new paper-plastic composite material:

[0066] The specific preparation method is as follows: first, corona treatment is performed on at least one side of the barrier layer plastic resin film layer 3, and the dyne value is ≥38. The paper-plastic separation water-based coating 2 is applied to one side of the base paper layer 1 and the corona surface of the barrier layer plastic resin film layer 3 by a coating process, and the side of the base paper layer 1 pre-coated with the paper-plastic separation water-based coating 2 and the side of the barrier layer plastic resin film layer 3 pre-coated with the paper-plastic separation water-based coating 2 are laminated, and then dried and cooled before winding, the drying temperature is 105±5°C, and the machine speed is 80 m / min.

[0067] The new paper-plastic composite material prepared in Example 3 of the present invention was tested, and the test results are as follows: Figure 2 and Figure 3 As shown, the new paper-plastic composite material made by the present invention can easily separate paper from plastic, and the base paper layer 1 and the plastic resin layer 3 are not damaged. After the service life ends, the paper and plastic can be easily separated and put into their respective recycling systems to complete the classified recycling of paper and plastic, and then reuse them, thereby reducing the cost and energy consumption of recycling.

[0068] Table 2: Physical and chemical properties of paper-plastic composite materials prepared in different embodiments

[0069]

[0070] The paper-plastic composite materials prepared in other examples were tested and the physical and chemical properties were similar to those in Example 1, indicating that the novel paper-plastic composite packaging material of the present invention has similar physical and chemical properties.

Claims

1. A paper-plastic composite packaging material, characterized in that: The paper-plastic composite packaging material comprises a first barrier layer plastic resin film layer, a second water-based coating layer and a third base paper layer; the barrier layer plastic resin film layer is polyethylene terephthalate PET, polypropylene PP or polyethylene PE; the PET resin film has a thickness of 6 to 20 μm; the base paper layer is 20-350 g / m² packaging paper; The water-based coating comprises 30-55% of an acrylate polymer, 0.1-0.5% of a defoamer, 1-5% of an aqueous wax emulsion, and the remainder is deionized water; the acrylate polymer is solid below 100°C after drying and is viscous above 100°C; the aqueous wax emulsion has a particle size of 10-500 nanometers; The preparation method of the paper-plastic composite packaging material is as follows: 1) adding acrylate polymer, defoamer, aqueous wax emulsion and deionized water into a dispersing stirring kettle, stirring and dispersing at 5-35° C. and a rotation speed of 200-1500 r / min for not less than 1 hour to obtain a water-based coating; 2) pre-coating the water-based coating on the corona surface of the barrier plastic resin film layer, drying it in a drying oven, then melting the water-based coating under heating, laminating it with the base paper layer, and obtaining the paper-plastic composite packaging material after cooling; The acrylate polymer is sold by Henkel AG of Germany under the product number LOCTITE LIOFOL HS2809-22RE.

2. The paper-plastic composite packaging material according to claim 1, characterized in that: The water-based paint comprises 35% by mass of acrylic polymer, 0.3% by mass of defoamer, 3% by mass of water-based wax emulsion and 61.7% by mass of deionized water.

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